There have been many years of development in designing compact umbrellas, typically following the same principle of utilising a taut wire to stiffen the spokes that support the canopy. The spokes are normally in 3 or 4 hinged segments, which are foldable, with the canopy fabric being gathered around them. Normally a pouch is also provided for storing the folded umbrella. There are a number of disadvantages of the conventionally designed compact umbrellas as listed below:
The supporting spokes are folded such that the canopy fabric is gathered around them and a substantial part of the wet side of the fabric is on the outside.
The folding process requires handling of the wet fabric and even when fully folded it does not prevent water dripping from it.
A separate pouch is required to store the folded umbrella and as much of the fabric is loose and wet, it is difficult to store in a cover pouch. It is also difficult to incorporate the cover and the lid as part of a single unit.
The arrangement of the spokes, fabric and the folding process limits capacity of the umbrella frame to resist turning inside out against wind. The wire supported hinged spokes have no inherent stiffness to right themselves if the umbrella is blown inside out in the wind. The hinge mechanism presented in this invention is inherently stiffer and more stable.
Various attempts have been made to improve on the conventional umbrella design but, for various reasons, none have yet met with any significant commercial success. For example GB2329123 (Harasawa) describes an umbrella having a cylindrical sleeve used either as a handle or for storing the umbrella. However, although collapsible, the umbrella in this invention still folds up with the wet side outermost. An umbrella, which folds up reversibly, is known from JP08056725 (Okumura). However, this is not of the collapsible type. Furthermore, any water trapped within the canopy fabric is simply free to drain out if the furled umbrella falls over or is inverted.
EP0596180 (Vincenzi) describes an umbrella, which collapses into a handle. Once again, this is not of the collapsible type and, from the geometry of the struts and ribs, it is doubtful if this could ever be erected.
GB9903285 (Kazim) describes an umbrella that attempts to solve the shortcomings outlined above, but which dispenses with a central spine.